Portland cement and process for producing the same



process for producin use? sa'r'rfei It is another object to provide a cement H E of this class in which, after the cement has seig-there will be a minimum amount of free lime.

other'object is the provision of a cement having as" one of the mgredients sufiiclent t e ee mew en wa er or othermoisten'ing' lngredlents are'added to the cement.

It is another object to provide a cement which'will assure a structure, when the cement 5 has set; which will be chemically 'safe' to a high degree, that is. less readily acted upon;

by active agent larly' sulphur water. a i It is another object to provide, a" cement which, whenset; will constitute arelatively insoluble com 'ound.

Another ob ect is the provision of a cementmaximum efficiency.

56 Another object is the provision ofla cement I in which the maximum amount of cementing qualities ma beattained. t Y 7 Another 0 ject is the provisionof a'pr'ocess for producing the type of cement mentioned The present invention is the cement which is now'commer'cially known in the United States" as supercement, ancfwhich is manufactured primarlly in accordance with the disclosure'of United States LettersPatingredients used-comprise a clinke mixed '45 with sum and tannicacid. t ough the pres n invention as resu ted from the handling and experimenting with the supercement referred w; it may also be 'use'd 1 with other grades and qualities of Portland cement although with perhaps less e clent ee chemicall active silica to combine with s, such as water, and partlcug mn eeh we e e outgrowth of the use of and' frequent experimentswith a" 0'." resultsitl ah nqwhzn used Where dtdinaryiPorflland cementiy'used it has beeiisnoted that amtasrdrms' of-cheniicaliyacthie'siliea m'a combined partially.

with f'heeali im oxi' eli'brated ItYthePOIt h laud'cement during: hydration; forming a cal:

mm conditions than mare have'g-been the akxiumhydroxide otlierwise'formedes been) disruvered tliat in thehydration -1ibefi atd2:ea;1ciuui:.ispresent ima colieidatforrrr i stimnlhtcdfilaird rendered -moreiefl ective by l"3 adjvstingithe-ipi oportiogrsilicato thechemibai 1 "requirements: of r the 4 particular supercemmt under consfderatiom andi byjintij Pm om use "mi" Iii?" ente 1 @ement'prodncedacordin th imfmml to qssessrqualitieeefwaterpr efing and: stren i'etcemtin -;those-,ol a1ry knfiwn kind= ofcement;eithert e Pbrtltind? {Zfilfiflbl the'supernement; when these 'knowmtypes of cement! are mixedwith: "chemically aetivy sillitaegi. :o ns'equenfly', theleoncrete resnlting from.the'rpresentr processqis remarkably re: sistant-to all. formszofexposure wmchtaatnarilytend to destroy the stability and-co;

p A hesivnrofeoncrete-inwlrich the cementisusedl ent' No. 1,214,9 1 0 issued'February 6th, 1917 ml F. Goddard In the supercement the 5? is wellilmowni cement which is used foe forming concrete structures consistsiofiffused eonibinations' whicl'i areflall anhydrous and withzmany'vanious' combinations in the ea y ment a peanftricalciumrsili'catefand (ii-caleiu'n'rxr. It is also. wellrknowmthat in the hjzd-ratiblifofi' this cement the triscal cisilicate will liberatetwomolecules'ofiealciunf aide-{While the a im silicate m0 witli'thesupercementg;

erate one molecule of'calcium oxide. It is also well known that the roportions of the tri-calcium silicate and t e di-calcium silicate which appear in the cement vary over wide limits so that incarrying out the. present process the proportions of these ingredients are important factors.

The solution, in carrying out the process. in order to arrive at the PIOdllCbdCSIIGd, is, the addition to the ground clinker of sufl i-" cient chemically active silica to properly com- ..a bine with the liberated 'limeor calcium oxide whch appears in thehydrated cement. It

has been discovered that for this purpose an;

admixture of trassblast furngce slagg gig-t0- maceous eart an 0 1e "mgr en s ns1 mg in whole or in art of chemically active sihca may be intro mad and used e ciently when'intimately mixed or ground with the cement clinker and calcium sulb When Wis um r carrying out the process the calcium sulphate will of course ave incorporated in it tannin or tannic g cg'd or a tannin waterproo g agen as so os in the patent referred to. The rocess, there- I ound cefore, consists in mixing with t e ment clinker and calcium sulphate avmg incorporated in it tannin or tannic acid or-a tannin waterproofin agent of predetermined y active silica. When amount of c emic structure of the clinker;

2. A method of making Portland cement comprising mixing the clmker with psum previously treated or incorporated w1th tannic'acid and mixin therewith a quantit of chemically active silica sufiicient to com ine with substantially all of the calcium oxide liberated upon hydration of the cement.

r 3. The process of mixing with a Portland cement consisting of ground clinker and col ciu'm sulphate having tannin incorporated in itof a predetermined amount of chemically active ,silica, depending upon chemlcal p s. a

this predetermined amount of chemicall ac- :'.::5 a :f 1.1-1;

tive silica, which is dependent upon the c emical constituents of the cement clinke added,thereisprovidedacement which when hydrated will possess little, if an free lime, i

the liberated calcium oxide com wing with I active silica so that a maxithe chemically mum cementin efiectis r0duced.--'

Thefresultso tained with the super cement f: being superior to the results obtained with ordinary Portland cement when the chemiacid is incorporated in thesupercement.

react upon the silicate mamtain the silica chemically active and reused from its do r mant state, should itbe in one,-so that it will combine with the calcium oxide, will 'cally active silica is added thereto,isbelieved due principally to the fact that the tannic efiect results superior to the results obtained by a mixture in which this reactive'agent is not present, and for the purpose of this dis-" tive closure tannic acid cited as such a "rea thus described my I claim as new and desire to secure by Letters Patent-'1 'J 'fifwr: g 5 i T;;i .=ii;' 15 d s 1 1 =A*?ortla nd cement consisting of "a 9 ground clinker and'gypsum, said gypsum having tannin' incorporated therein, and a quantityfof chemically active silica'substam tially'sufiicient to combine with the calcium oxide liberated upon the hydration of the invention what 

